1. Field of the Invention
The present invention relates to a strengthened copper including a dispersed carbide.
2. Prior Art
To provide an electrically conductive material having a sufficient strength in a high temperature, there has been used a strengthened copper including dispersed particles consisting of alumina or the like. The strengthened copper may be called a particle dispersed, strengthened copper. The strengthened copper is produced basically by a process of powder metallurgy. For example, regarding an oxide strengthened copper, a powder copper raw material is mixed with copper oxide powder. Subsequently, the particles of the copper oxide powder can be evenly dispersed in matrices of the copper elements during oxidation due to the copper oxide powder. Meanwhile, a carbide dispersed copper is obtained by mixing a powder copper raw material with a carbide in a mechanical alloying process.
Thus produced copper alloys are formed into electric conductors in desired product sizes by the plastic forming of hot extrusion after solidification thereof.
However, these known strengthened coppers have been little commercially produced because of a significantly high production cost due to their long, complicated production processes.
To solve the problem, modified molding methods have been proposed However, a satisfactory result has not been attained For example, Japanese Patent Laid-open No. 2-19177 proposes a method, in which carbide particulates are added in pure copper and they are molten by heating. The melt is mechanically stirred at a high speed of 1500 rpm and is cooled until solidification of the melt. This forcibly evenly disperses the carbide particulates in matrixes of copper elements. However, such stirring apparatuses are high in installation cost, and moreover, this method provides only a product having a low tensile strength of the order of 400 N/mm.sup.2 (newton/square millimeter).